1. Field of the Invention
The present invention relates to an alternator for use in an automotive vehicle, and more particularly to such an alternator having a driving pulley with end flanges.
2. Description of Related Art
Generally, an alternator for use in an automobile is driven by an engine via a driving belt coupled to a pulley of the alternator. When a so-called poly-V belt having plural V-shaped projections is used as the driving belt, the poly-V belt has to be correctly positioned relative to plural pulley grooves formed on the pulley. That is, the plural V-shaped projections of the driving belt have to be engaged with the plural pulley grooves, so that the V-belt is correctly positioned in the axial direction within a width of the pulley. For this purpose, a pulley having end flanges formed at both axial ends of the pulley is proposed, as exemplified in JP-B2-3509292.
It is not easy, however, to make end flanges having a relatively large diameter, especially when the pulley is made of a steel plate by stamping. If the diameter of the flanges is not sufficiently large, the poly-V belt may not be correctly positioned relative to an axial width of the pulley. Further, water may enter into a bearing of the alternator through an axial gap between the pulley and an axial end of a bearing holder. The bearing may be damaged with the water, and thereby noises may be generated and a life of the alternator may be shortened.